Simplify the expression. $(-2a^{4}+6a^{2})(-a^{4}-2a)$
First use the distributive property. $ - 2 a^4 (- a^4) - 2 a^4 (-2 a) + 6 a^2 (- a^4) + 6 a^2 (-2 a) $ Simplify. $2a^{8}-6a^{6}+4a^{5}-12a^{3}$